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Cosmological Inflation, Dark Matter and Dark Energy

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A special issue of Symmetry (ISSN 2073-8994). This special issue belongs to the section "Physics".

Deadline for manuscript submissions: closed (30 June 2019) | Viewed by 39514

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Special Issue Editor

Dr. Kazuharu Bamba

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Guest Editor

Faculty of Symbiotic Systems Science, Fukushima University, Fukushima 960-1296, Japan
Interests: particle cosmology; gravity theory; inflation; late time acceleration
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Based on the recent cosmological observations, such as Type Ia Supernovae, cosmic microwave background (CMB) radiation large scale structure, baryon acoustic oscillations (BAO) and weak lensing, the universe has experienced the accelerated phase of its expansion not only in the early universe but also in the present time. The former is called "inflation" and the latter is called "the late-time cosmic acceleration". It is also well known that the three energy components of the universe are dark energy (about 68%), dark matter (about 27%) and baryon (about 5%).

A number of studies have been executed for the origins of the field to realize inflation, dark matter and dark energy, which are most fundamental problems in modern physics and cosmology. The future detection of the primordial gravitational waves is strongly expected in order to know the energy scale of the inflationary phase. Moreover, there are two possibilities for the origin of dark matter, namely, new particles in particle-theory models beyond the standard model and astrophysical objects. Furthermore, there have been proposed two representative studies for the true character of dark energy. One is the introduction of some unknown matter called dark energy with the negative pressure in the framework of general relativity. The other is the modification of gravity at large scales, leading to the so-called geometrical dark energy.

The main aim of this special issue is to understand various cosmological aspects of inflation, dark matter and dark energy. In addition to the phenomenological approaches, more fundamental studies are considered from higher-dimensional theories of gravity, quantum gravity and quantum cosmology, physics in the early universe, quantum field theories and gauge field theories in curved spacetime, and strings, branes and holographic principle. It is very pleased to receive submissions to this special issue on inflation, dark matter, dark energy and related foundations of physics.

Prof. Dr. Kazuharu Bamba
Guest Editor

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Keywords

inflation
dark matter
dark energy
cosmology
modified gravity theories
higher-dimensional theories of gravity
quantum gravity and quantum cosmology
primordial gravitational waves
physics in the early universe
particle-theory models beyond the standard model
quantum field theories and gauge field theories in curved spacetime
strings, branes and holographic principle

Published Papers (13 papers)

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Research

17 pages, 395 KiB

Open AccessArticle

Cosmological Consequences of a Parametrized Equation of State

by Abdul Jawad, Shamaila Rani, Sidra Saleem, Kazuharu Bamba and Riffat Jabeen

Symmetry 2019, 11(8), 1009; https://doi.org/10.3390/sym11081009 - 05 Aug 2019

Cited by 14 | Viewed by 2545

Abstract

We explore the cosmic evolution of the accelerating universe in the framework of dynamical Chern–Simons modified gravity in an interacting scenario by taking the flat homogeneous and isotropic model. For this purpose, we take some parametrizations of the equation of state parameter. This parametrization may be a Taylor series extension in the redshift, a Taylor series extension in the scale factor or any other general parametrization of

ω

. We analyze the interaction term which calculates the action of interaction between dark matter and dark energy. We explore various cosmological parameters such as deceleration parameter, squared speed of sound, Om-diagnostic and statefinder via graphical behavior. Full article

(This article belongs to the Special Issue Cosmological Inflation, Dark Matter and Dark Energy)

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12 pages, 304 KiB

Open AccessArticle

Effect of Quantum Gravity on the Stability of Black Holes

by Riasat Ali, Kazuharu Bamba and Syed Asif Ali Shah

Symmetry 2019, 11(5), 631; https://doi.org/10.3390/sym11050631 - 05 May 2019

Cited by 38 | Viewed by 2824

Abstract

We investigate the massive vector field equation with the WKB approximation. The tunneling mechanism of charged bosons from the gauged super-gravity black hole is observed. It is shown that the appropriate radiation consistent with black holes can be obtained in general under the condition that back reaction of the emitted charged particle with self-gravitational interaction is neglected. The computed temperatures are dependant on the geometry of black hole and quantum gravity. We also explore the corrections to the charged bosons by analyzing tunneling probability, the emission radiation by taking quantum gravity into consideration and the conservation of charge and energy. Furthermore, we study the quantum gravity effect on radiation and discuss the instability and stability of black hole. Full article

(This article belongs to the Special Issue Cosmological Inflation, Dark Matter and Dark Energy)

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8 pages, 240 KiB

Open AccessArticle

The Lanczos Equation on Light-Like Hypersurfaces in a Cosmologically Viable Class of Kinetic Gravity Braiding Theories

by Bence Racskó and László Á. Gergely

Symmetry 2019, 11(5), 616; https://doi.org/10.3390/sym11050616 - 02 May 2019

Cited by 4 | Viewed by 2459

Abstract

We discuss junction conditions across null hypersurfaces in a class of scalar–tensor gravity theories (i) with second-order dynamics, (ii) obeying the recent constraints imposed by gravitational wave propagation, and (iii) allowing for a cosmologically viable evolution. These requirements select kinetic gravity braiding models with linear kinetic term dependence and scalar field-dependent coupling to curvature. We explore a pseudo-orthonormal tetrad and its allowed gauge fixing with one null vector standing as the normal and the other being transversal to the hypersurface. We derive a generalization of the Lanczos equation in a 2 + 1 decomposed form, relating the energy density, current, and isotropic pressure of a distributional source to the jumps in the transverse curvature and transverse derivative of the scalar. Additionally, we discuss a scalar junction condition and its implications for the distributional source. Full article

(This article belongs to the Special Issue Cosmological Inflation, Dark Matter and Dark Energy)

46 pages, 594 KiB

Open AccessEditor’s ChoiceArticle

Hadronic and Hadron-Like Physics of Dark Matter

by Vitaly Beylin, Maxim Yu. Khlopov, Vladimir Kuksa and Nikolay Volchanskiy

Symmetry 2019, 11(4), 587; https://doi.org/10.3390/sym11040587 - 23 Apr 2019

Cited by 28 | Viewed by 3550

Abstract

The problems of simple elementary weakly interacting massive particles (WIMPs) appeal to extend the physical basis for nonbaryonic dark matter. Such extension involves more sophisticated dark matter candidates from physics beyond the Standard Model (BSM) of elementary particles. We discuss several models of dark matter, predicting new colored, hyper-colored or techni-colored particles and their accelerator and non-accelerator probes. The nontrivial properties of the proposed dark matter candidates can shed new light on the dark matter physics. They provide interesting solutions for the puzzles of direct and indirect dark matter search. Full article

(This article belongs to the Special Issue Cosmological Inflation, Dark Matter and Dark Energy)

25 pages, 588 KiB

Open AccessArticle

Cosmological Consequences of New Dark Energy Models in Einstein-Aether Gravity

by Shamaila Rani, Abdul Jawad, Kazuharu Bamba and Irfan Ullah Malik

Symmetry 2019, 11(4), 509; https://doi.org/10.3390/sym11040509 - 08 Apr 2019

Cited by 20 | Viewed by 2646

Abstract

In this paper, we reconstruct various solutions for the accelerated universe in the Einstein-Aether theory of gravity. For this purpose, we obtain the effective density and pressure for Einstein-Aether theory. We reconstruct the Einstein-Aether models by comparing its energy density with various newly proposed holographic dark energy models such as Tsallis, Rényi and Sharma-Mittal. For this reconstruction, we use two forms of the scale factor, power-law and exponential forms. The cosmological analysis of the underlying scenario has been done by exploring different cosmological parameters. This includes equation of state parameter, squared speed of sound and evolutionary equation of state parameter via graphical representation. We obtain some favorable results for some values of model parameters Full article

(This article belongs to the Special Issue Cosmological Inflation, Dark Matter and Dark Energy)

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17 pages, 282 KiB

Open AccessArticle

Alternative Uses for Quantum Systems and Devices

by Orchidea Maria Lecian

Symmetry 2019, 11(4), 462; https://doi.org/10.3390/sym11040462 - 02 Apr 2019

Cited by 1 | Viewed by 2118

Abstract

Quantum optical systems and devices were analyzed to verify theories both predicting new particles on flat spacetime, and for the verification of Planck-scale physics for cosmological investigation. Full article

(This article belongs to the Special Issue Cosmological Inflation, Dark Matter and Dark Energy)

18 pages, 391 KiB

Open AccessEditor’s ChoiceArticle

Spacetime Symmetry and LemaîTre Class Dark Energy Models

by Irina Dymnikova and Anna Dobosz

Symmetry 2019, 11(1), 90; https://doi.org/10.3390/sym11010090 - 15 Jan 2019

Cited by 6 | Viewed by 3250

Abstract

We present the regular cosmological models of the Lemaître class with time-dependent and spatially inhomogeneous vacuum dark energy, which describe relaxation of the cosmological constant from its value powering inflation to the final non-zero value responsible for the present acceleration in the frame of one self-consistent theoretical scheme based on the algebraic classification of stress-energy tensors and spacetime symmetry directly related to their structure. Cosmological evolution starts with the nonsingular non-simultaneous de Sitter bang, followed by the Kasner-type anisotropic expansion, and goes towards the present de Sitter state. Spacetime symmetry provides a mechanism of reducing cosmological constant to a certain non-zero value involving the holographic principle which singles out the special class of the Lemaître dark energy models with the global structure of the de Sitter spacetime. For this class cosmological evolution is guided by quantum evaporation of the cosmological horizon whose dynamics entirely determines the final value of the cosmological constant. For the choice of the density profile modeling vacuum polarization in a spherical gravitational field and the GUT scale for the inflationary value of cosmological constant, its final value agrees with that given by observations. Anisotropy grows quickly at the postinflationary stage, then remains constant and decreases to

A < 10^{- 6}

when the vacuum density starts to dominate. Full article

(This article belongs to the Special Issue Cosmological Inflation, Dark Matter and Dark Energy)

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15 pages, 758 KiB

Open AccessArticle

Tsallis, Rényi and Sharma-Mittal Holographic Dark Energy Models in Loop Quantum Cosmology

by Abdul Jawad, Kazuharu Bamba, Muhammad Younas, Saba Qummer and Shamaila Rani

Symmetry 2018, 10(11), 635; https://doi.org/10.3390/sym10110635 - 13 Nov 2018

Cited by 46 | Viewed by 3783

Abstract

The cosmic expansion phenomenon is being studied through the interaction of newly proposed dark energy models (Tsallis, Rényi and Sharma-Mittal holographic dark energy (HDE) models) with cold dark matter in the framework of loop quantum cosmology. We investigate different cosmic implications such as [...] Read more.

ω_{d}

ω_{d}^{'}

ω_{d}

and

ω_{d}^{'}

represent the equation of state (EoS) parameter and its evolution, respectively). It is found that EoS parameter exhibits quintom like behavior of the universe for all three models of HDE. The squared speed of sound represents the stable behavior of Rényi HDE and Sharma-Mittal HDE at the latter epoch while unstable behavior for Tsallis HDE. Moreover,

ω_{d}

ω_{d}^{'}

plane lies in the thawing region for all three HDE models. Full article

(This article belongs to the Special Issue Cosmological Inflation, Dark Matter and Dark Energy)

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13 pages, 450 KiB

Open AccessFeature PaperArticle

Dark Matter as a Non-Relativistic Bose–Einstein Condensate with Massive Gravitons

by Emma Kun, Zoltán Keresztes, Saurya Das and László Á. Gergely

Symmetry 2018, 10(10), 520; https://doi.org/10.3390/sym10100520 - 17 Oct 2018

Cited by 7 | Viewed by 3412

Abstract

We confront a non-relativistic Bose–Einstein Condensate (BEC) model of light bosons interacting gravitationally either through a Newtonian or a Yukawa potential with the observed rotational curves of 12 dwarf galaxies. The baryonic component is modeled as an axisymmetric exponential disk and its characteristics are derived from the surface luminosity profile of the galaxies. The purely baryonic fit is unsatisfactory, hence a dark matter component is clearly needed. The rotational curves of five galaxies could be explained with high confidence level by the BEC model. For these galaxies, we derive: (i) upper limits for the allowed graviton mass; and (ii) constraints on a velocity-type and a density-type quantity characterizing the BEC, both being expressed in terms of the BEC particle mass, scattering length and chemical potential. The upper limit for the graviton mass is of the order of

10^{- 26}

eV / c^{2}

, three orders of magnitude stronger than the limit derived from recent gravitational wave detections. Full article

(This article belongs to the Special Issue Cosmological Inflation, Dark Matter and Dark Energy)

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16 pages, 283 KiB

Open AccessFeature PaperArticle

Dark Energy and Dark Matter Interaction: Kernels of Volterra Type and Coincidence Problem

by Alexander B. Balakin and Alexei S. Ilin

Symmetry 2018, 10(9), 411; https://doi.org/10.3390/sym10090411 - 18 Sep 2018

Cited by 9 | Viewed by 3133

Abstract

We study a new exactly solvable model of coupling of the Dark Energy and Dark Matter, in the framework of which the kernel of non-gravitational interaction is presented by the integral Volterra-type operator well-known in the classical theory of fading memory. Exact solutions of this isotropic homogeneous cosmological model were classified with respect to the sign of the discriminant of the cubic characteristic polynomial associated with the key equation of the model. Energy-density scalars of the Dark Energy and Dark Matter, the Hubble function and acceleration parameter are presented explicitly; the scale factor is found in quadratures. Asymptotic analysis of the exact solutions has shown that the Big Rip, Little Rip, Pseudo Rip regimes can be realized with the specific choice of guiding parameters of the model. We show that the Coincidence problem can be solved if we consider the memory effect associated with the interactions in the Dark Sector of the universe. Full article

(This article belongs to the Special Issue Cosmological Inflation, Dark Matter and Dark Energy)

12 pages, 292 KiB

Open AccessFeature PaperArticle

Topological Gravity Motivated by Renormalization Group

by Taisaku Mori and Shin’ichi Nojiri

Symmetry 2018, 10(9), 396; https://doi.org/10.3390/sym10090396 - 11 Sep 2018

Cited by 1 | Viewed by 2444

Abstract

Recently, we have proposed models of topological field theory including gravity in Mod. Phys. Lett. A 2016, 31, 1650213 and Phys. Rev. D 2017, 96, 024009, in order to solve the problem of the cosmological constant. The Lagrangian densities of the models are BRS (Becchi-Rouet-Stora) exact and therefore the models can be regarded as topological theories. In the models, the coupling constants, including the cosmological constant, look as if they run with the scale of the universe and its behavior is very similar to the renormalization group. Motivated by these models, we propose new models with an the infrared fixed point, which may correspond to the late time universe, and an ultraviolet fixed point, which may correspond to the early universe. In particular, we construct a model with the solutions corresponding to the de Sitter space-time both in the ultraviolet and the infrared fixed points. Full article

(This article belongs to the Special Issue Cosmological Inflation, Dark Matter and Dark Energy)

15 pages, 458 KiB

Open AccessArticle

Decaying Dark Energy in Light of the Latest Cosmological Dataset

by Ivan De Martino

Symmetry 2018, 10(9), 372; https://doi.org/10.3390/sym10090372 - 01 Sep 2018

Cited by 10 | Viewed by 2934

Abstract

Decaying Dark Energy models modify the background evolution of the most common observables, such as the Hubble function, the luminosity distance and the Cosmic Microwave Background temperature–redshift scaling relation. We use the most recent observationally-determined datasets, including Supernovae Type Ia and Gamma Ray [...] Read more.

H (z)

and Cosmic Microwave Background temperature versus z data and the reduced Cosmic Microwave Background parameters, to improve the previous constraints on these models. We perform a Monte Carlo Markov Chain analysis to constrain the parameter space, on the basis of two distinct methods. In view of the first method, the Hubble constant and the matter density are left to vary freely. In this case, our results are compatible with previous analyses associated with decaying Dark Energy models, as well as with the most recent description of the cosmological background. In view of the second method, we set the Hubble constant and the matter density to their best fit values obtained by the Planck satellite, reducing the parameter space to two dimensions, and improving the existent constraints on the model’s parameters. Our results suggest that the accelerated expansion of the Universe is well described by the cosmological constant, and we argue that forthcoming observations will play a determinant role to constrain/rule out decaying Dark Energy. Full article

(This article belongs to the Special Issue Cosmological Inflation, Dark Matter and Dark Energy)

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10 pages, 484 KiB

Open AccessArticle

New Holographic Dark Energy Model in Brans-Dicke Theory

by M. Sharif, Syed Asif Ali Shah and Kazuharu Bamba

Symmetry 2018, 10(5), 153; https://doi.org/10.3390/sym10050153 - 11 May 2018

Cited by 12 | Viewed by 3008

Abstract

We study the cosmic evolution of the Bianchi type I universe by using new holographic dark energy model in the context of the Brans-Dicke theory for both non-interacting and interacting cases between dark energy and dark matter. We evaluate the equation of state [...] Read more.

ω_{D}

and draw the

ω_{D} - {\dot{ω}}_{D}

plane, where the dot denotes the time derivative. It is found that a stage in which the cosmic expansion is accelerating can be realized in both cases. In addition, we investigate the stability of the model by analyzing the sound speed. As a result, it is demonstrated that for both cases, the behavior of the sound speed becomes unstable. Furthermore, with the Om-diagnostic tool, it is shown that the quintessence region of the universe can exist. Full article

(This article belongs to the Special Issue Cosmological Inflation, Dark Matter and Dark Energy)

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